Enhanced Triplet State of Coralyne via DNA-Templated Gold Nanostars

Localized surface plasmon resonance (LSPR) effects in gold nanoparticles (AuNPs) significantly influence the excited states of nearby molecules, offering unique opportunities for enhancing molecular triplet states. Herein, we report the synthesis of DNA-templated gold nanostars (AuNF_A15) and gold nanospheres (AuNS_T15) via a seed-mediated growth method and their ability to enhance the triplet state of coralyne, a small molecule with promising applications in photodynamic therapy (PDT). DNA single strands (A15 or T15) were employed as templates to regulate the morphology of AuNPs, resulting in nanostars and nanospheres. The nanostars exhibited a superior LSPR effect due to their "lightning rod effect," significantly enhancing coralyne's triplet signal by 15-fold compared to a 10-fold enhancement observed with nanospheres. This enhancement was confirmed via steady-state and nanosecond transient absorption spectroscopy. These findings demonstrate that DNA-assembled gold nanostars hold exceptional potential for enhancing molecular triplet states, particularly for PDT applications involving DNA-targeting small molecules.